64 ANTHOZOA HYDROIDA. 



A small species not exceeding an inch in height, and well distin- 

 guished by its strongly wrinkled cells, which resemble a barrel in 

 miniature. Polypidoms gregarious, the shoots united by a radical 

 branching fibre, erect or creeping, annulated between the cells, 

 simple or sparingly branched, the branches irregular, patent. Cells 

 crowded, alternate, subsessile, ovate, coarsely wrinkled, especially 

 when dried, contracted at the orifice which is obsoletely quadriden- 

 tate. The ovarian vesicles are sparingly evolved, and differ from the 

 cells only in being a little larger, and in having three teeth in the 

 opening at the top of each. As a parasite, it does not confine itself 

 to Flustra foliacea, as Pallas would have us to believe ; but infests 

 the roots and stems of many sea- weeds. 



There is a variety of this species, parasitical on Plumularia fal- 

 cata, which, in habit and in the remoteness of the cells, resembles 

 Sert. polyzonias. The cells are also more cylindrical or ovate than 

 ordinary. The constantly submerged state in which this variety 

 grows may account for its peculiarities, which certainly bring it very 

 near to the figure of Sert. polyzonias in Ellis, pi. 2, fig. A, but from 

 which it is distinguished by the coarsely wrinkled cells. (Fig. 8, c.) 



The Sert. patagonica of D'Orbigny does not appear to be distinct 

 from S. rugosa. Mr. W. Thompson has specimens, on algse, from 

 California. 



** Cells in pairs, opposite or semi-alternate. 



3. S. ROSACE A, cells opposite, tubulous, the upper half free 

 and divergent, ike aperture entire, truncate ; vesicles crowned 

 with spines. Ellis. 



PLATE XI. FIG. 1. 



Lily or Pomegranate-flowering Coralline, Ellis Corall. 8, no. 7, pi. 4, fig. a. A. 



Phil. Trans, abridg. x. 492, pi. 12, fig. 5, s. H. Sertularia rosacea, Lin. Syst. 



1306. Ellis and Soland. Zooph. 39. Esper Pflanz. Sert. tab. 20, fig. 13. 

 Lam. Anim. s. Vert. ii. 119. Johnston in Trans. Newc. Soc. ii. 258. Templeton 

 loc. cit. 468. Couch Zooph. Corn. 7 ; Corn. Faun. iii. 18. Macgillivray in Ann. 

 Nat. Hist. ix. 463. Sert. nigellastrum, Pall. Elench. 129. Sert. abietina? 

 Fabric. Faun. Groenl. 442. Dynamena rosacea, Lamour. Cor. Flex. 175. Flem. 

 Brit. Anim. 544. 



Hob. Frequent on corallines, and occasionally on old shells 

 from deep water. 



Polypidom from one to two inches in height, attached by a creep- 

 ing tortuous tubular fibre, very slender and delicate, of a white or 



